#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;



class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * max increasing subsequence
     * @param arr int整型vector the array
     * @return int整型
     */
    int MLS(vector<int>& arr) {
        // write code here
        sort(arr.begin(), arr.end());
        int n = arr.size(), ret = 0;
        for (int i = 0; i < n;)
        {
            int j = i + 1, count = 1;
            while (j < n)
            {
                if (arr[j] - arr[j - 1] == 1)
                {
                    count++;
                    j++;
                }
                else if (arr[j] - arr[j - 1] == 0)
                {
                    j++;
                }
                else
                {
                    break;
                }
            }
            ret = max(ret, count);
            i = j;
        }

        return ret;
    }
};